1. Field of the Invention
The present invention relates to a document inverting-and-transporting apparatus having a configuration in which a two-sided document bearing images on the two faces is inverted, and more particularly to a document inverting-and-transporting apparatus which is to be mounted on an image reading apparatus having a reading unit which reads an image of a document.
2. Description of the Related Art
Conventionally, a document inverting-and-transporting apparatus that is configured so that a document the surface of which has been read is inverted and then transported, and the rear face is read is disclosed in JP-A-Sho.62-21665, etc. In the apparatus of JP-A-Sho.62-21665, a document is fed from a feeding portion disposed above the apparatus to a guide plate, then transported onto a platen glass disposed in a lower portion along a U-like guide portion disposed in the guide plate, and when the front end of the document abuts against one end of the platen glass, the document is stopped. A reading process is then conducted. While setting the rear end foremost, the document is thereafter passed through a inlet port of an inversion path opened in one end side of the platen glass, to enter the inversion path which is formed in a U-turn path by a pair of thin metal plates, and then upward transported to be again fed to the guide portion through an outlet port which is opened in the middle of the guide portion. The document in a state in which the face is inverted with respect to that in the previous operation is transported onto the platen glass, and the reading process is then conducted.
In the thus configured document inverting-and-transporting apparatus, plural transport rollers serving as a unit for transporting a document are arranged at intervals in the transport path. When the distance between the transport rollers is set to be shorter than the minimum length of a document used in the document inverting-and-transporting apparatus, the transported state of a document is always maintained by at least two of the transport rollers, so that the document can be surely transported. When the length of the inversion-and-transport path is set to be longer than the maximum length of a document used in the document inverting-and-transporting apparatus, the front and rear ends of an inverted document do not overlap with each other, so that a transport failure due to overlapping of a document and a damage of front and rear ends of a document can be prevented from occurring.